The present invention relates generally to recording mode locking systems in video signal magnetic recording apparatuses, and more particularly to a recording mode locking system in a video signal magnetic recording and/or reproducing apparatus having a mechanism for pulling out a magnetic tape from within a cassette upon recording or reproduction modes to load the magnetic tape unto a predetermined tape path and performing an unloading operation in which the magnetic tape is accommodated within the cassette upon stopping mode, which does not unload the magnetic tape and restarts to continue performing a recording operation in a state where the magnetic tape is loaded unto the predetermined tape path when a power source switch is turned OFF during a recording mode and the power source switch is turned back ON afterwards.
Generally, a video signal magnetic recording and/or reproducing apparatus (hereinafter referred to as a VTR) which uses a cassette which accommodates a magnetic tape therein, is provided with a loading mechanism for pullsing out the magnetic tape from within the cassette upon recording or reproduction modes to load the magnetic tape unto a predetermined tape path and performing an unloading operation in which the magnetic tape is accommodated within the cassette upon stopping mode. A VTR provided with this type of a loading mechanism is constructed so that the loading mechanism performs an unloading operation when the VTR is put into a stopping mode upon completion or discontinuation of the recording or reproduction.
In a VTR of the above type, when the power source is turned OFF in the recording mode without changing the operation mode into a stopping mode, each mechanism within the VTR remain in the same states as those when the power source was turned OFF, and the magnetic tape is in the loaded state, however, when the power source is next turned ON, the operation mode of the VTR is generally always automatically put into the stopping mode so that the loading mechanism automatically performs an unloading operation. This function is provided so that no inconveniences are introduced regardless of which operation mode is selected after the power source switch is turned back ON, since the stopping mode in which the magnetic tape is accommodated within the cassette is the starting point (original point) from which various operation modes such as recording, reproduction, fast-forward, and rewind modes are initiated.
On the other hand, in a portable VTR which records a video signal produced from an image pickup output obtained by the use of an image pickup camera, an internal battery is used as the power source. Generally, the capacity of this type of a battery is not large, and thus, in order to reduce the power consumption, the power source is often turned OFF when the VTR is not operated. For example, a so-called continuous recording of different programs is often performed in which the power source is onced turned OFF due to the termination of recording of one program, change in the object which is to be image-picked up, or operator's will, after the image of a scene is recorded, and the power source is turned ON after a certain time interval has elapsed to restart and continue the recording.
Accordingly, in the conventional apparatus, the loading mechanism once automatically performs an unloading operation as described above when the power source is turned ON after the power source has been turned OFF. Therefore, when a recording button is next pushed and operated, the loading mechanism performs a loading operation in which the magnetic tape is loaded unto a predetermined tape path to start the recording operation. However, when the magnetic tape which is in a loading state is once unloaded and accommodated within the cassette, and then pulled out from within the cassette to load the magnetic tape, the former recording finishing end position on the magnetic tape with respect to the video head of the guide drum is not accurately returned back into the original position before the unloading operation was performed, and a slight deviation in the magnetic tape position is introduced. This slight deviation in the magnetic tape position is of course introduced when the feeding of the magnetic tape upon loading and the take-up of the magnetic tape upon unloading are respectively performed by use of different reels, however, the above slight deviation in the magnetic tape position is also introduced when the same reel is used upon the above described loading and unloading of the magnetic tape.
When deviation exists between the recording starting position and the previous recording finishing end position in the magnetic tape as described above, the recording starting position and the recording finishing end position in the magnetic tape sometimes overlap, or in some cases, a non-recorded part is formed in the magnetic tape between the recording finishing position and the recording starting position. In a case where these overlapping part or non-recorded part is reproduced, inconsistency in the picture, and noise bar are introduced in the reproduced picture. In addition, when recording is to be performed in a state where the above undesirable effects are not introduced, the power source must constantly be turned ON, and this resulted in unnecessary power consumption.